I believe that you can do anything your brain could in it's waking state. To explain this more simply I'll use an example; say you're an artist and seeking to make a new piece of art. Normally in the waking world your brain can collect information together, mix it all into a big pot and come out with a new idea, completely self created and influenced by everything you've collected. In a dreaming state your brain can still do this, but can still only work off of information it has already collected. For instance if you had no idea about the Crimean war your dreams cannot suddenly tell you about it, however they can present you with new ideas based off of what you already have.
You can do anything you know about in the waking world but cannot artificially create information out of the blue, everything has to be based on information you already have. People having spiritual realisations in dreams (ignoring the really out of body stuff) is normally your brain just presenting information you already know but may not have thought of, or in a different way to the norm.